Phase Noise and Fading Effects on System Performance in MT-DS-SS

Document Type


Subject Area(s)

Electrical and Computer engineering


Multicarrier (MC) modulation and code division multiple access (CDMA) schemes have seen much recent attention for the high capacities and flexibility they can provide. A potential difficulty with these systems is their sensitivity to the effects of imperfect frequency up/down conversion due to local oscillator phase noise and frequency offset. In this paper, we provide a general method to upper bound and/or approximate system performance in multitone direct-sequence spread spectrum (MT-DS-SS) signaling in the presence of imperfect synchronization. We model phase noise as a slow random processes with small variance. In particular, we assume coherent detection with binary phase-shift keying (BPSK) modulation and use a phase noise model based upon one for a practical phase-locked loop (PLL). Comparisons between simulations and analysis show excellent agreement, and also show that system degradation is dominated by the common phase noise, and that the intersubcarrier-same-user interference (IS-SUI) contribution is very small. The approach we employ provides an effective analytical/numerical method for performance evaluation for low target error probability values, on the order of 10/sup -6/ or lower. In addition, our method can also be easily applied to any multicarrier system with other frequency offset/phase noise models.